并网逆变器数字化控制算法优化设计

Optimization Design of Digital Control Algorithm for Grid Connected Inverter

数字控制器存在的固有控制时延会影响并网逆变器入网电流的控制性能,为此提出一种控制算法优化方案,旨在降低控制时延带来的不利影响。首先分析了控制时延以及零阶保持器对比例-积分(propor⁃tional-integral,PI)控制器参数稳定域及系统阶跃响应的影响,在此基础上提出采用超前环节来补偿控制时延带来的相角滞后,分析不同补偿参数下的性能差异并选定了最优补偿参数,经过超前环节补偿后的PI控制算法能拓宽PI参数的稳定域以及提升控制系统动态性能。最后,利用Matlab/Simulink仿真平台以及并网逆变器样机验证了所提算法的有效性与实用性。

The inherent control delay of the digital controller may affect the control performance of the current of grid-connected inverter.For this reason,a control algorithm optimization scheme was proposed to reduce the adverse effect of control delay.Firstly,the influences of control delay and zero-order hold on the parameters stability region of proportional-integral(PI)controller and step response of system were analyzed.On this basis,a leading link based compensator was proposed to compensate the phase lag caused by control delay,whilst the performance difference under various compensation parameters was also analyzed.Therefore the optimal compensation parameter was selected and determined.And the PI control algorithm with compensator based on leading link could broaden the stability region of PI parameters and improve the dynamic performance of control system.Finally,the validity and effectiveness of the proposed algorithm were verified via the Matlab/Simulink simulation platform and a grid-connected inverter prototype.